1. Field of the Invention
The present invention relates generally to a personal computer which allows selective use of an integrally-provided keyboard and an optionally-connectable external keyboard, and more particularly to a personal computer which is improved such that the integral and external keyboards can both be controlled by use of a single keyboard controller.
2. Description of the Related Art
Recent years have seen the development of the so-called laptop computer, which is basically a portable personal computer. Some models laptop are provided with a foldable flat panel type display, such as a plasma display, which, when the computer is not in use, can be folded down onto the main body, such that it covers the computer's integral keyboard. This feature, together with relatively light weight and compact dimensions, makes the device easy to carry around from place to place.
To further improve their portability, some recently-developed laptop computers employ a small integral keyboard. Since the number of keys provided in a smaller-size integral keyboard is generally less than that provided in a standard size keyboard, such as that used in a desk-top type personal computer, two or more functions therefore may be assigned to individual keys provided in the integral keyboard. However, assigning multiple functions to individual keys tends to render keyboard operation more complex. Thus, the smaller size integral keyboard tends to be inferior to the standard size keyboard, from the point of view of the keyboard operability.
With this in mind, several recently developed laptop computers have been designed so that an external keyboard having a larger number of keys than the integral keyboard can be optionally connected to them. When such an external keyboard is connected, the laptop type computer in question can be used in the same manner as the desk top type personal computer.
However, in order that both types of keyboards can be used, individual keyboard controllers -one for the integral keyboard and the other for the external keyboard- must be provided, thus increasing the number of parts or components required in the laptop computer, and increasing the manufacturing cost thereof.